In the quenching process for shovel or other hardware that involve large amount of continuous operation, spray rising water and leaching/drip washing water converge into liquid storage tank. Over time, the concentration of quenching medium, as well as the liquid volume increase in the storage tank. In general, there are three temperature levels of liquid storage to recover the quenching medium by using temperature differential method. When the quenching medium concentration reaches a critical level, the medium will be crystallized in the bottom of storage tank. Because of the temperature difference among the levels in the liquid storage tank, medium crystals dominantly appear in in the third level of the tank that has the lowest temperature. To recover the medium crystal, the common practice is to take out the crystal from the tank manually, then dry the crystal out, in order to recycle the crystal. The disadvantage of this existing method is, first of all, large area is necessary for drying the medium crystal, and secondly, not only this manual taking out and drying process wastes human labor, also, it can be significantly interrupted by the influence of the natural environment such as unfavorable weather, limitation of space, and additionally, is can cause secondary pollution.
The temperature of the quenching medium increases along with the continuous process of production, and cooling procedure is necessary to ensure the quenching quality. The existing technique involves installing water-cooling pipe to cool down the quenching medium in the quenching tank. The disadvantages of this existing technique are: first of all, water wasting, and secondly, pipeline blockage by scale deposition, which needs to be regularly maintained and repaired to ensure the quenching quality.